The announcement came after a USA drone strike Friday killed top Iranian military commander Qasem Soleimani in Iraq, sparking fury in Iran which has vowed to avenge his death.
US West Texas Intermediate CLc1 crude was at $64.39 a barrel, up $1.34, or 2.1%, after touching $64.44 earlier, the highest since April.
Described as the second most powerful man in Iran, Suleimani was killed in a drone strike at a Baghdad airport in Iraq, . The killing has heightened concerns of a widening Middle East conflict that could disrupt oil supplies from a region that accounts for almost half of the world's oil production.
Trump also threatened sanctions against Baghdad after Iraq's parliament called on United States troops to leave the country. Retired Gen. David Petraeus, an ex-CIA director and former commander of US forces in Iraq, said he believes the administration needs a strategy for tamping down the chances of all-out war.
Ties have deteriorated after an American precision drone strike Friday on the Baghdad worldwide airport that killed Iran's Major General Qasem Soleimani and top Iraqi military figure Abu Mahdi al-Muhandis.
Trump also said the USA would strike back "perhaps in a disproportionate manner", but Hathaway noted that's a violation of worldwide law.
The consultancy expects oil prices in 2020 to range from $65 to $75 a barrel, based on rising risks to oil infrastructure in the region.
Iran's supreme leader Ayatollah Ali Khamenei vowed "severe revenge" and declared three days of mourning.
She cited legal problems with both of Trump's Saturday threats - the threat to hit 52 targets in Iran for symbolic reasons, and the threat to strike Iranian cultural sites.
With China, "we in particular noted our agreement.to urge Iran to avoid any new violation of the Vienna accord", he added.
Pompeo tip-toed around questions about Trump's tweet Saturday threatening to attack Iranian cultural sites, a military action that likely would be illegal under the laws of armed conflict and the United Nations charter. In insisting that any U.S. attacks will be legal, Pompeo said Trump "was getting to this point" without making it in his tweet Saturday.
"We'll behave inside the system", Pompeo said.
In a separate interview on Fox News on Sunday, Pompeo claimed Trump never said he would order attacks on cultural sites if they struck Americans or American assets, something Trump did tweet on Saturday.
The US soldiers stationed across Iraqi bases are deployed as part of the broader worldwide coalition, invited by the Iraqi government in 2014 to help fight IS.
In a reaction to the US withdrawal from the landmark 2015 Iranian nuclear deal in May 2018 and the subsequent sanctions, and in a response to the Europe's sluggishness in facilitating Iran's banking transactions and its oil exports, Iran, since May 2019, made staged moves to drop its nuclear commitments.
Earlier Sunday, the Iraqi Parliament voted to obligate Iraq's government "to work towards ending the presence of all foreign troops on Iraqi soil", according to the media office of the Iraqi Parliament. "Why not delay?' And why this one is so unsafe is that he is truly taking us right to the edge of war", she said. "We will continue to do things appropriately, lawfully, and constitutionally". In this case, the killing of an American contractor, the wounding of others, and the subsequent embassy protests "crossed his line".
"I think the real question for the United States is, will there be a diplomatic initiative that says, OK, look, this is not headed in a good direction".
For Iran's army chief, Trump's threat was an attempt to distract the world from Soleimani's "unjustifiable" assassination.